Antoni Carraro heater not working

[MrAntonio]

Hey

So i got an Antonio Carraro K327 and the heater stopped working so its only blowing cold air.

We found out the 2lines that goes to the roof, only one of these get warm.
To me that says there is no circulation.

Would it be a block in the heater itself or a faulty hose?
Anyone had this issue?

Does these machines have a thermostat taht could be faulty maybe?

Checked the manuel but no info on the heater system..

Thanks